Motion in a Straight Line

A real board, not a video.

This board is from a different Physics lesson — yours will look like this. She writes and draws while she explains, and stops to check you followed.

Doubts this lesson clears up

• Why does the same motion look different from a train window and from the platform?
• Can displacement be negative even if I moved forward?
• When do average speed and average velocity give the same number?
• How can I find instantaneous velocity without calculus?
• Why does a negative area under a velocity‑time graph mean the object moved backward?
• If a boat moves upstream at 3 m s⁻¹ and the river flows at 2 m s⁻¹, what is its speed relative to the bank?